Police reveal reason behind human leg found on highway near Darwin

A human leg was found on the Stuart Hwy near Darwin. Photo / NT News

Authorities are racing to find a person whose lower leg was found on a major Australian highway this week, as they believe the person could still be alive.

Police confirmed a "lower leg of a dark-skinned human being" was found on Tuesday morning on Stuart Highway near Coolalinga, about 29 kilometres south east of Darwin.

A motorist reported the shocking find to police about 10.30am and a forensic pathologist confirmed by the afternoon that it was in fact a human leg.

On Wednesday, Detective Senior Sergeant Paul Morrissey said their investigation had found there had been "some sort of vehicle versus pedestrian collision", believed to have happened between 8pm and 9pm on Monday.

"The owner of the leg has not been identified, nor the rest of the person," he said, according to NT News.

Sgt Morrissey said information suggested the person survived but said they would have needed medical treatment as soon as possible.

A human leg was found on the Stuart Hwy near Darwin. Photo / NT News

Media had been told on Tuesday no other human remains were found and inquires were being made to hospitals and clinics, but Sgt Morrissey said no one had been found with injuries that could have been sustained from the incident.

A passing motorist told NT News on Tuesday they spotted what looked like "most of a leg and foot" on Monday night.

"I thought for sure that I didn't just see part of a human leg and didn't actually believe myself until this morning, when I saw they found human remains on the highway," he said.

Stuart Hwy was closed between the Howard Springs lights and Virginia Road on Tuesday morning and reopened in the evening.

It was reported more than 20 police cars were seen dotted along the Stuart Hwy for about 1km at midday as a crime scene was established.

Police are asking for witnesses or anyone who may have been driving in the area, who has dashcam footage since Monday afternoon, to contact police on 131 444 and quote reference 10020603.